DBMS_LOBSUBSTR
DBMS_LOB.SUBSTR is a function in Oracle database management system (DBMS) that is used to extract a portion of a large object (LOB) value. LOBs are special data types used to store large amounts of data, such as text, images, or audio, in a database.
The DBMS_LOB.SUBSTR function takes four arguments:
- lob_loc: the LOB value from which to extract the substring
- amount: the number of bytes or characters to extract
- offset: the starting position in the LOB value from which to extract the substring
- csid: the character set ID (optional)
The function returns a substring of the LOB value specified by lob_loc, starting at the position specified by offset and extending for the number of bytes or characters specified by amount. If the amount argument is larger than the remaining length of the LOB value after the starting position, the function returns the remaining portion of the LOB value.
The csid argument specifies the character set ID to use for character-based LOBs. If this argument is not specified, the LOB value is assumed to be in the default character set of the database
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